It was Scotty’s iconic line from Star Trek, which of course broke the laws of physics every episode. This goes beyond Sci-Fi though and into the world of thrillers and adventure, whether books, TV or films.

The special effects geek in ‘When the Dust Settles’ explains to Maddy that if a film director wants a man thrown backwards by a shot from a puny 0.38, he’s not going to object. As a sometime scientist, the laws of physics as employed in fiction are important in maintaining my suspension of disbelief. All fiction requires this. We need to believe that lone investigator can crack the case that has the police baffled, that heroic archaeologist can find that lost city when everyone else has failed, that secret agent can overpower the evil genius’ goons. Even if we need to believe in magic, dragons, aliens or vampires, that belief comes easier if the non-fantastic elements of the plot match our own experience of universal laws.

Which is where physics come in. Action sequences can be difficult to portray in books. I sometimes think ‘who’s been punched? Whose hand is on whose throat? Where’s the knife now?’ so tend to keep action sequences simple in my Flint series. In ‘Glint..’ the immense Battle of Cambrai is portrayed poetically, with a taut single viewpoint conveying the confusion of battle without my character ducking from each shell and moving from ruin to ruin. Not only the laws of physics but the laws of chance seem to be against the men of the Royal Guernsey Light Infantry.

TV and film though thrives on action, and directors delight in breaking Mr Newton’s laws as well as those covering Thermodynamics, basic human physiology and statistical probability. Number one sin is hanging onto a cliff edge by the fingertips, leaping and grabbing ropes or chains or helicopter skids mid air. Just about possible for a stuntman or circus performer with a good deal of practice, not for our average hero. That pact with the scriptwriter is broken and I no longer believe what I’m being shown -even in fantasy such as the Hobbit trilogy. It’s also been done so many times before its just boring (sorry, Hooten & the Lady).

Falling from heights is in the same category. I was gratified to see the SAS hunk in the latest ‘Our Girl’ hospitalised after a mere 15-foot heroic dive onto a beach whilst grappling a terrorist (and using him to break the fall). Yes people can fall off mountains, out of tall trees, jump from planes into the sea and survive, but generally they will have multiple fractures or have their internal organs re-organised by the experience.

Kick-ass heroines fighting men. Okay if she has some special martial art she can deploy involving throws and dodges, or can stab with a pointed weapon fast and skilfully, but an average man is so much stronger than even an athletic woman. A fight involving fists, grappling, blows with edged weapons, or grabbing at a knife hand is likely to end just one way. Especially as our heroine is usually young, lithe and wearing impractical attire.

Then there’s ballistics. We’re getting better on the whole of recognising what a mess a bullet can make of the human body. The degree we portray this is largely dictated by the certificate we want our film to have, or whether it will be screened post-watershed. There is still room for the ‘bang you’re dead’ approach to gunfights, as seen in the Bond movies; we don’t want Saving Private Ryan every night. However there is danger in this fantasy approach to guns – our hero shoots on the move (very little chance of hitting anything), he shoots from the hip (little chance of hitting anything beyond a few feet away), he shoots with both hands (how does he aim?) or he blasts away with a machine gun (when the recoil means that after 4 or 5 shots his bullets will be going up in the air somewhere). This lack of reality may indeed help fuel the bizarre American love affair with firearms.

I won’t even mention car chases…

Peril is not exciting if our hero is not facing a risk of actual death or maiming. Yes we want them to survive and yes we know they are a cut above armchair adventurers such as me, but it is a lazy cheat to allow him/her to bend universal laws when the writer has written his hero into a corner. Much better if s/he can use their intelligence, training, experience and skill to get out of the situation. Rather than shout ‘Never!’ at the screen or throw the book down in disgust, we are instead impressed by the cleverness of the writer.